I've not done it but a quick Google search shows that in other cars they just screw in/out. Comments suggest they are screwed in VERY tight and folks used a cloth or something to protect the old pins then pliers to unscrew them. I don't know if this is applicable to the S so ymmv.
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!